Fenestrated stent grafts

ABSTRACT

A stent graft ( 1 ) including a tubular wall ( 3 ) with at least one fenestration ( 40 ) including a peripheral ( 37 ) reinforcement around at least part of the fenestration. There can also be a tubular extension ( 15 ). The side arm includes a stent ( 19 ) and a cover ( 17 ) and extends from and is in fluid communication with the fenestration and the stent graft. The stent may be a self expanding stent. The ring and/or tubular extension provides better support and sealing for an extension arm. The fenestration ( 40 ) can be circular or if towards the ends of the stent graft may be in the form of a U-shape ( 50 ) with an open end.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of Ser. No. 10/962,765, filed Oct. 12,2004, now U.S. Pat. No. 7,413,573, which claims priority of provisionalapplication Ser. No. 60/510,241 filed Oct. 10, 2003 and provisionalapplication Ser. No. 60/529,346 filed Dec. 12, 2003, which areincorporated by reference in their entirety.

TECHNICAL FIELD

This invention relates to a stent graft adapted for endovasculardeployment and in particular to a fenestrated stent graft.

BACKGROUND OF THE INVENTION

In our earlier patent application published as WO 99/29262 there wasdisclosed a stent graft including at least one fenestration to enable anextension leg graft to be extended from a main stent graft in aninternal lumen through the fenestration to have the extension leg or armgraft extend into a branch vessel of the lumen. Such a situation mayexist in the aorta with renal arteries extending from the aorta. Whenthere is an aneurysm in this region which includes the junction of theaorta with the renal arteries then it is desirable to not only have amain graft which spans the aneurysm but also extension legs or armswhich extend from the main graft into the renal or other arteries.

A simple fenestration does not necessarily give a fully reliable supportand sealing surface for the extension leg graft and it is the object ofthis invention to improve the ability for support and sealing of anextension leg or arm grafts into a main graft.

SUMMARY OF THE INVENTION

In one form, therefore, the invention is said to reside in a stent grafthaving a tubular wall and at least one fenestration in the tubular wall,the or each fenestration including a resilient material around at leasta portion of the periphery thereof to provide dimensional stability tothe fenestration.

Preferably the resilient material may be selected from Nitinol,stainless steel or elastomeric material and may be in the form of aspring, expandable ring such as a slip ring or a portion of resilientwire.

In one form the resilient material around the periphery may be in theform of a ring.

Preferably the ring includes at least two turns of wire and preferablythe terminal ends of the wire of the ring are provided with a loop sothat the wire does not present a pointed end of wire which could damagea vessel.

Alternatively, the ring may be a ring of a resilient material such as anelastomer. The elastomer may for instance be silicone elastomer.

Where the fenestration is adjacent an end of the stent graft thefenestration may be in the form of a scallop which is open at one side.The resilient material around the periphery may be in the form of aU-shape and during deployment may assist with opening up of thefenestration so that a vessel behind the fenestration can becatheterized.

In another embodiment of a fenestration in the form of a scallopprovided at the distal or proximal end of the stent graft, it may havestruts of self expanding stents acting as resilient peripheralreinforcement around a portion of the fenestration. When the stentexpands upon deployment, the struts spread apart thereby opening up thefenestration.

The scallop may be at the proximal or distal end of a stent graft. Forinstance, when deploying a stent graft extending from the thoracic arch,a fenestration may be provided to prevent the coeliac artery beingoccluded. As with all embodiments, radiopaque or MRI opaque markers maybe used to define the periphery of the fenestration.

When deploying a stent graft into the lower aorta in the region of theaortic bifurcation, it may be desirable to provide a scallopedfenestration at the proximal end of the stent graft to avoid occludingthe renal arteries or the superior mesenteric artery. Where thesearteries are close together the scalloped fenestration may be of such asize that it extends over more than one of the openings to the arteries.

The U-shape of resilient material can be a Nitinol or a stainless steelwire or may be a portion of an elastomeric material such as a siliconeelastomer.

The fenestration may be surrounded by radiopaque markers to assist withvisualisation by suitable radiographic techniques. Alternatively theremay be included in or associated with the resilient material a gold orother heavy metal wire or band to provide the necessary visualisation.

In one embodiment the fenestration may include a tubular extensionbetween the tubular wall and the ring.

The tubular extension may include a self expanding stent and anassociated lining or covering of a biocompatible graft material.

In an alternative form the invention is said to reside in a stent grafthaving at least one fenestration, the fenestration including a tubularextension, the side arm including a stent and extending from and influid communication with the fenestration and the tubular wall.

Preferably the tubular extension includes an associated lining orcovering of a biocompatible graft material. By this arrangement theinner cylindrical surface of the tubular extension provides a largersupport and sealing surface between the fenestration in the main graftand an outer cylindrical surface of a side branch stent graft which hasbeen deployed through the fenestration.

Preferably the stent in the tubular extension is a self expanding stentwhich may be Nitinol™ or stainless steel. Alternatively the stent in thetubular extension may be a balloon expandable stent.

In one form the stent may be in the form of a well-known Gianturco stylezig zag Z stent. Alternatively the stent may be a Nitinol self expandingstent of the type known as a ZILVER™ stent sold by Cook Incorporated,Bloomington, Ind.

The bio-compatible graft material may be either on the inside or theoutside of the stent or there may be a cover which extends over both theinside and the outside of the stent on the tubular extension.

There may be further included a ring of a resilient material around theperiphery at the terminal end of the tubular extension to providedimensional stability to the tubular extension to assist with sealing.The ring may be formed from one or more and preferably two or morecircular turns of Nitinol or stainless steel wire and preferably have aloop at each of its ends to prevent the wire from presenting a sharp endwhich might protrude through the graft material and pierce a lumen wall.

The bio-compatible material may be dacron, Thoralon™, expandedpolytetrafluoroethylene or other synthetic bio-compatible material.

While Dacron, expanded polytetrafluoroethylene (ePTFE), or othersynthetic biocompatible materials can be used to fabricate the coveringsfor the stent graft and the tubular extension, a naturally occurringbiomaterial, such as collagen, is highly desirable, particularly aspecially derived collagen material known as an extracellular matrix(ECM) material, such as small intestinal submucosa (SIS) commerciallyavailable from Cook Biotech, West Lafayette, Ind. Besides SIS, examplesof ECM's include pericardium, stomach submucosa, liver basementmembrane, urinary bladder submucosa, tissue mucosa, and dura mater.

SIS is particularly useful, and can be made in the fashion described inBadylak et al., U.S. Pat. No. 4,902,508; Intestinal Collagen Layerdescribed in U.S. Pat. No. 5,733,337 to Carr and in 17 NatureBiotechnology 1083 (November 1999); Cook et al., WIPO Publication WO98/22158, dated 28 May 1998, which is the published application ofPCT/US97/14855. Irrespective of the origin of the material (syntheticversus naturally occurring), the material can be made thicker by makingmultilaminate constructs, for example SIS constructs as described inU.S. Pat. Nos. 5,968,096; 5,955,110; 5,885,619; and 5,711,969. Animaldata show that the SIS used in grafts can be replaced by native tissuein as little as a month's time. In addition to xenogenic biomaterials,such as SIS, autologous tissue can be harvested as well. AdditionallyElastin or Elastin-Like Polypetides (ELPs) and the like offer potentialas a material to fabricate the graft to form a device with exceptionalbiocompatibility. Another alternative would be to use allographs such asharvested native tissue. Such tissue is commercially available in acryopreserved state.

The tubular extension may be placed on a reduced diameter portion of thestent graft so that the overall diameter of the stent graft is notsignificantly affected.

For this specification the term ‘tubular extension’ in relation to theside arm, is intended to mean that the length of the tubular extensionis substantially similar in order of magnitude to the diameter of thetubular extension. Hence for a tubular extension diameter of 6millimetres the length may be in the range of 5 to 10 millimetres. Sucha tubular extension diameter would be suitable for deploying anextension leg or arm graft for a renal artery extending from an aorta.

The stent graft may have a diameter of from 20 to 40 mm and a length offrom 100 to 250 mm. The placement of the-fenestrations and the tubularextensions where required is dependant upon the particular body lumenand each set of fenestrations would normally be custom designed. Themain stent graft may include a proximally extending uncovered stent toassist with retention within a body lumen such as an aorta.

The main stent graft in which the fenestration is provided may be one ofthe components of a composite graft.

U.S. Pat. No. 5,387,235 entitled “Expandable Transluminal GraftProsthesis For Repair Of Aneurysm” discloses apparatus and methods ofretaining grafts onto deployment devices. These features and otherfeatures disclosed in U.S. Pat. No. 5,387,235 could be used with thepresent invention and the disclosure of U.S. Pat. No. 5,387,235 isherewith incorporated in its entirety into this specification.

U.S. Pat. No. 5,720,776 entitled “Barb and Expandable Transluminal GraftProsthesis For Repair of Aneurysm” discloses improved barbs with variousforms of mechanical attachment to a stent. These features and otherfeatures disclosed in U.S. Pat. No. 5,720,776 could be used with thepresent invention and the disclosure of U.S. Pat. No. 5,720,776 isherewith incorporated in its entirety into this specification.

U.S. Pat. No. 6,206,931 entitled “Graft Prosthesis Materials” disclosesgraft prosthesis materials and a method for implanting, transplantingreplacing and repairing a part of a patient and particularly themanufacture and use of a purified, collagen based matrix structureremoved from a submucosa tissue source. These features and otherfeatures disclosed in U.S. Pat. No. 6,206,931 could be used with thepresent invention and the disclosure of U.S. Pat. No. 6,206,931 isherewith incorporated in its entirety into this specification.

PCT Patent Publication No. WO 98/53761 entitled “A Prosthesis And AMethod And Means Of Deploying A Prosthesis” discloses an introducer fora prosthesis which retains the prosthesis so that each end can be movedindependently. These features and other features disclosed in PCT PatentPublication No. WO 98/53761 could be used with the present invention andthe disclosure of PCT Patent Publication No. WO 98/53761 is herewithincorporated in its entirety into this specification.

U.S. Pat. No. 6,524,335 and PCT Patent Publication No. WO 99/29262entitled “Endoluminal Aortic Stents” disclose a fenestrated prosthesisfor placement where there are intersecting arteries. This feature andother features disclosed in U.S. Pat. No. 6,524,335 and PCT PatentPublication No. WO 99/29262 could be used with the present invention andthe disclosure of U.S. Pat. No. 6,524,335 and PCT Patent Publication No.WO 99/29262 is herewith incorporated in its entirety into thisspecification.

U.S. patent application Ser. No. 10/280,486, filed Oct. 25, 2002 andpublished on May 8, 2003 as U.S. Patent Application Publication No.US-2003-0088305-A1 and PCT Patent Publication No. WO 03/034948 entitled“Prostheses For Curved Lumens” discloses prostheses with arrangementsfor bending the prosthesis for placement into curved lumens. Thisfeature and other features disclosed in U.S. patent application Ser. No.10/280,486, and U.S. Patent Application Publication No.US-2003-0088305-A1 and PCT Patent Publication No. WO 03/034948 could beused with the present invention and the disclosure of U.S. Patentapplication Ser. No. 10/280,486, and U.S. Patent Application PublicationNo. US-2003-0088305-A1 and PCT Patent Publication No. WO 03/034948 isherewith incorporated in its entirety into this specification.

U.S. Provisional Patent Application Ser. No. 60/392,682, filed Jun. 28,2002, U.S. patent application Ser. No. 10/447,406, filed May 29, 2003,and Published on Dec. 18, 2003, as U.S. Patent Application PublicationNo. US-2003-0233140-A1, and PCT Patent Publication No. WO 03/101518entitled “Trigger Wires” disclose release wire systems for the releaseof stent grafts retained on introducer devices. This feature and otherfeatures disclosed in U.S. Provisional Patent Application Ser. No.60/392,682, U.S. patent application Ser. No. 10/447,406, and U.S. PatentApplication Publication No. US-2003-0233140-A1, and PCT PatentPublication No. WO 03/101518 could be used with the present inventionand the disclosure of U.S. Provisional Patent Application Ser. No.60/392,682, U.S. patent application Ser. No. 10/447,406, and U.S. PatentApplication Publication No. US-2003-0233140-A1, and PCT PatentPublication No. WO 03/101518 is herewith incorporated in its entiretyinto this specification.

U.S. Provisional Patent Application Ser. No. 60/392,667, filed Jun.28,2002, and U.S. patent application Ser. No. 10/609,846, filed Jun. 30,2003, and Published on May 20, 2004, as US Patent ApplicationPublication No. US-2004-0098079-A1, and PCT Patent Publication No. WO2004/028399 entitled “Thoracic Deployment Device” disclose introducerdevices adapted for deployment of stent grafts particularly in thethoracic arch. This feature and other features disclosed in U.S.Provisional Patent Application Ser. No. 60/392,667, U.S. patentapplication Ser. No. 10/609,846, and US Patent Application PublicationNo. US-2004-0098079-A1, and PCT Patent Publication No. WO 2004/028399could be used with the present invention and the disclosure of U.S.Provisional Patent Application Ser. No. 60/392,667, U.S. patentapplication Ser. No. 10/609,846, and US Patent Application PublicationNo. US-2004-0098079-A1, and PCT Patent Publication No. WO 2004/028399 isherewith incorporated in its entirety into this specification.

U.S. Provisional Patent Application Ser. No. 60/392,599, filed Jun. 28,2002, and U.S. patent application Ser. No. 10/609,835, filed Jun. 30,2003, and published on Jun. 3, 2004, as U.S. Patent ApplicationPublication No. US-2004-0106978-A1, and PCT Patent Publication No. WO2004/002370 entitled “Thoracic Aortic Aneurysm Stent Graft” disclosestent grafts that are useful in treating aortic aneurysms particularlyin the thoracic arch. This feature and other features disclosed in U.S.Provisional Patent Application Ser. No. 60/392,599, U.S. patentapplication Ser. No. 10/609,835, and U.S. Patent Application PublicationNo. US-2004-0106978-A1, and PCT Patent Publication No. WO 2004/002370could be used with the present invention, and the disclosure of U.S.Provisional Patent Application Ser. No. 60/392,599, U.S. patentapplication Ser. No. 10/609,835, and U.S. Patent Application PublicationNo. US-2004-0106978-A1, and PCT Patent Publication No. WO 2004/002370 isherewith incorporated in its entirety into this specification.

U.S. Provisional Patent Application Ser. No. 60/391,737, filed Jun. 26,2002, U.S. patent application Ser. No. 10/602,930, filed Jun. 24, 2003,and PCT Patent Publication No. WO 2004/002365 entitled “Stent-GraftFastening” disclose arrangements for fastening stents onto graftsparticularly for exposed stents. This feature and other featuresdisclosed in U.S. Provisional Patent Application No. 60/391,737, U.S.patent application Ser. No. 10/602,930, and PCT Patent Publication No.WO 2004/002365 could be used with the present invention and thedisclosure of U.S. Provisional Patent Application Ser. No. 60/391,73,U.S. patent application Ser. No. 10/602,930, and PCT Patent PublicationNo. WO 2004/002365 are herewith incorporated in its entirety into thisspecification.

U.S. Provisional Patent Application Ser. No. 60/405,367, filed Aug. 23,2002, U.S. patent application Ser. No. 10/647,642, filed Aug. 25, 2003,and PCT Patent Publication No. WO 2004/017868 entitled “Asymmetric StentGraft Attachment” disclose retention arrangements for retaining onto andreleasing prostheses from introducer devices. This feature and otherfeatures disclosed in U.S. Provisional Patent Application Ser. No.60/405,367, filed Aug. 23, 2002, U.S. patent application Ser. No.10/647,642, filed Aug. 25, 2003, and PCT Patent Publication No. WO2004/017867 could be used with the present invention and the disclosureof U.S. Provisional Patent Application Ser. No. 60/405,367, filed Aug.23, 2002, U.S. patent application Ser. No. 10/647,642, filed Aug. 25,2003, and PCT Patent Publication No. WO 2004/017867 are herewithincorporated in its entirety into this specification.

U.S. patent application Ser. No. 10/322,862, filed Dec. 18, 2002 andpublished as Publication No. US2003-0120332, and PCT Patent PublicationNo. WO03/053287 entitled “Stent Graft With Improved Adhesion” disclosearrangements on stent grafts for enhancing the adhesion of such stentgrafts into walls of vessels in which they are deployed. This featureand other features disclosed in U.S. patent application Ser. No.10/322,862, filed Dec. 18, 2002 and published as Publication No.US2003-0120332, and PCT Patent Publication No. WO03/053287 could be usedwith the present invention and the disclosure of U.S. patent applicationSer. No. 10/322,862, filed Dec. 18, 2002 and published as PublicationNo. US2003-0120332, and PCT Patent Publication No. WO03/053287 areherewith incorporated in its entirety into this specification.

U.S. Provisional Patent Application Ser. No. 60/405,769, filed Aug. 23,2002, U.S. patent application Ser. No. 10/645,095, filed Aug. 23, 2003,and PCT Patent Publication Number WO 2004/017867 entitled “CompositeProstheses” discloses prostheses or stent grafts suitable forendoluminal deployment. These prostheses and other features disclosed inU.S. Provisional Patent Application Ser. No. 60/405,769, filed Aug. 23,2002, U.S. patent application Ser. No. 10/645,095, filed Aug. 23, 2003,and PCT Patent Publication Number WO 2004/017867, could be used with thepresent invention and the disclosure of U.S. Provisional PatentApplication Ser. No. 60/405,769, filed Aug. 23, 2002, U.S. patentapplication Ser. No. 10/645,095, filed Aug. 23, 2003, and PCT PatentPublication Number WO 2004/017867 are herewith incorporated in itsentirety into this specification.

BRIEF DESCRIPTION OF THE DRAWING

This then generally describes the invention but to assist withunderstanding reference will now be made to the accompanying drawingswhich show a preferred embodiment of the invention.

In the drawings:

FIG. 1 shows one embodiment of a stent graft according to thisinvention;

FIG. 2 shows a cross section of the stent graft shown in FIG. 1 alongthe line 2-2′;

FIG. 3 shows a cross section through a tubular extension in oneembodiment of the invention;

FIG. 4 shows a part cut away view of the embodiment shown in FIG. 3;

FIG. 5 shows an alternative embodiment of a stent graft according tothis invention;

FIG. 6 shows a cross section through a fenestration shown in FIG. 5;

FIG. 7 shows a part cut away view of a fenestration of the embodimentshown in FIG. 5;

FIG. 8 shows a detailed view of the inside of a scalloped fenestrationaccording to one embodiment of the invention;

FIG. 9 shows an inside view of the embodiments shown in FIG. 8;

FIG. 10 shows an alternative embodiment of fenestration with a resilientelastomer ring surrounding the periphery of the fenestration;

FIG. 11 shows another view of the embodiment of FIG. 10;

FIG. 12 shows an alternative embodiment of a stent graft with ascalloped fenestration;

FIG. 13 shows a detailed internal view of the scalloped fenestration ofFIG. 12;

FIG. 13A shows an internal view of an alternative arrangement of ascalloped fenestration;

FIG. 14 shows an alternative embodiment of a stent graft with ascalloped fenestration; and

FIG. 15 shows a detailed internal view of the scalloped fenestration ofFIG. 14.

DETAILED DESCRIPTION

Now looking more closely at the drawings and in particular theembodiment shown in FIGS. 1 and 2 it will be seen that a main stentgraft 1 comprises a tubular wall body portion 3 at proximal and distalends of the stent graft 1 with a central reduced diameter portion 5between the ends of the stent graft with tapered portions 6 and 7extending from the tubular wall body portions 3 at each end to thecentral reduced diameter portion 5.

All of the tubular wall body portions, the tapered portions and thecentral portion are a biocompatible graft material such as Dacron,Thoralon™, expanded PTFE material or a naturally occurring biomaterial,such as an extracellular matrix, such as small intestinal submucosa orother suitable material or a combination of these materials.

Gianturco style zig zag Z stents 9 are provided inside the graftmaterial of the tubular body portions 3 at each end and in between theends Gianturco zig zag style Z stents 11 are provided on the taperingportions 6 and 7 and on the reduced diameter portion 5 outside of thegraft material. There may be further Gianturco style zig zag Z stents oneach of the tubular wall body portions 3, the tapering portions 6 and 7and the reduced diameter portion 5 depending upon the overall length ofthe stent graft 1.

In the reduced diameter central portion 5 there is at least onesubstantially circular fenestration or aperture 13 on the tubular wallof the stent graft. In this embodiment there are three fenestrationsbeing one for each of the two renal arteries and one for the superiormesenteric artery. Other numbers of fenestrations may also be used. Thefenestrations 13 are substantially circular and extending from thefenestrations are tubular extensions 15. The tubular extensions 15comprise a bio-compatible material tube 17 with a self expanding stent19. In this embodiment the self expanding stent 19 is provided on theouter surface of the tubular extension but in an alternative embodimentthe self expanding stent 19 may be provided on the inner surface of thegraft material 17.

The biocompatible material tube 15 is a biocompatible graft materialsuch as Dacron, Thoralon™, expanded PTFE material or a naturallyoccurring biomaterial, such as an extracellular matrix, such as smallintestinal submucosa or other suitable material as previouslyidentified.

Stitching 21 is provided to retain the tubular extension to the maingraft.

Radiopaque markers 23 are provided at each end of the fenestration 13 atthe base of the tubular extension 15 to assist a physician to locate thefenestration in respect to a side vessel extending from a main vessel.The radiopaque markers 23 may be gold or other convenient material.

In the embodiment shown in FIGS. 3 and 4 the tubular extension generallyshown as 30 extends from a fenestration or aperture 31 in the side wallof a main stent graft 32. The tubular extension 30 includes a selfexpanding Nitinol stent 34 with a bio-compatible graft material innerlayer 35 and outer layer 36. A ring 37 of Nitinol around the peripheryof the tubular extension at the terminal end 39 is provided to give gooddimensional stability to the distal end of the tubular extension 30. Inan alternative arrangement the ring 37 may be formed from stainlesssteel or any other convenient material. Stitching 41 is provided toretain the tubular extension to the main graft and stitching 42 is usedto retain the ring 37 at the terminal end 39 of the tubular extension30.

The ring 37 of Nitinol comprises two turns of wire with a loop 38 ateach end of the wire. The loops 38 are provided to prevent the chance ofdamage to lumen wall because the pointed end of the wire is effectivelyenclosed within the loop.

It will be seen that by these various embodiments of this form of theinvention that the tubular extension provides a good support and sealingsurface into which another bio-compatible material stent graft may bedeployed to extend into a branch artery from a main artery or otherlumen of the body.

FIGS. 5 to 7 show an alternative embodiment of a stent graft accordingto this invention. In this embodiment the same reference numerals asused in FIG. 1 are used for corresponding components.

A main stent graft 1 comprises a tubular wall body portion 3 at proximaland distal ends of the stent graft 1 with a central tubular wall bodyportion 5.

All of the tubular wall body portions are a biocompatible graft materialsuch as Dacron, Thoralon™, expanded PTFE material or a naturallyoccurring biomaterial, such as an extracellular matrix, such as smallintestinal submucosa or other suitable material.

Gianturco style zig zag Z stents 9 are provided inside the graftmaterial of the tubular wall body portions 3 at each end and on thecentral tubular wall body portion 5 Gianturco style zig zag Z stents 11are provided on the outside of the graft material. There may be furtherGianturco style zig zag Z stents on each of the tubular wall bodyportions 3 and the central tubular wall portion 5 than those illustrateddepending upon the overall length of the stent graft 1.

In the central tubular wall body portion 5 there is at least onesubstantially circular fenestration or aperture 40 on the tubular wallof the stent graft. In this embodiment there are two fenestrations beingone for each of the two renal arteries when this embodiment is deployedinto the aorta. Other numbers of fenestrations may also be used wherethe placement of the stent graft involves the possibility of occludingother branch vessels such as the superior mesenteric artery. Thefenestrations 40 are substantially circular. Radiopaque markers 23 areprovided at each end of the fenestration 40 to assist a physician tolocate the fenestration 40 in respect to a side vessel extending from amain vessel. The radiopaque markers 23 may be gold or other convenientmaterial.

A ring 45 of Nitinol as can particularly be seen in FIGS. 6 and 7 isprovided around the periphery of the fenestration 40 to give gooddimensional stability to the fenestration 40. In an alternativearrangement the ring 45 may be formed from stainless steel or any otherconvenient material. Stitching 47 is provided to retain the ring 45around the periphery of the fenestration 40.

The ring 45 of Nitinol preferably comprises at least two turns of wirewith a loop 49 at each end of the wire. The loops 49 are provided toprevent the chance of damage to lumen wall because the pointed ends ofthe wire are effectively enclosed within the respective loops.

Alternatively one of the wires 45 may be a gold or other biocompatibleheavy metal wire to provide radiographic visualisation of the ring toassist with positioning of the graft with respect to the branch vessel.Also in FIG. 5 there is shown a scalloped fenestration 50 which opens tothe end 52 of the stent graft. Detail of the scalloped fenestration 50can be seen in FIGS. 8 and 9.

FIG. 8 shows an external view of a scalloped fenestration which can beplaced at either the distal or proximal end of a stent graft and FIG. 9shows an internal view of the fenestration shown in FIG. 8. Thefenestration comprises a scallop of graft material cut out of the bodyof the graft 3. As can be seen in FIG. 9 an arch of resilient wire 52 isstitched around the periphery 54 of the scalloped fenestration. The wire52 has a loop 56 formed at each end of it so that no sharp end of thewire is provided which could damage the wall of a vessel into which thestent graft is deployed. Because the wire or other material from whichthe U-shaped reinforcement 52 is resilient the fenestration will closeup when the stent graft is in a contracted state for deployment into abodily lumen such as the aorta and when released will open up to enableblood flow through the fenestration to a branch vessel.

The arch of resilient wire 52 is preferably made from a number ofstrands, such as three strands, of a resilient wire such as Nitinol. Thewire is stitched to the periphery of the fenestration with stitches 53.

FIGS. 10 and 11 show two views of an alternative fenestrationarrangement according to the invention. In this embodiment thefenestration 60 is provided in the tubular wall 5 of a stent graft andsurrounding the fenestration 60 and providing reinforcement is anelastomeric ring 62 of a material such as silicon elastomer. Theelastomeric ring 62 is sewn by stitching 64 into the periphery of thefenestration 60. Once again the elastomeric ring can be deformed so thatit can be deployed within a deployment device and will open into theshape of the fenestration when deployed. The elastomeric ring willprovide a certain amount of resiliency in position of the fenestrationover a branch vessel and if deploying a side arm through thefenestration the elastomeric ring will provide a degree of blood sealingonto the branch stent graft.

FIGS. 12 and 13 show an alternative arrangement of fenestration on astent graft. In FIG. 12 the stent graft 68 comprises a tubular wall bodyof graft material 70 with a lumen therethrough. The distal end 72 of thestent graft has distally extending exposed stent 74 and within thetubular wall body 70 there are proximal and distal internal stents 76and 78 respectively and at least one external stent 80 intermediate theproximal distal ends. A fenestration is provided at the distal end 72 ofthe stent graft 68. In this embodiment the fenestration 82 is in theform of a scallop extending from the distal end 72 of the stent graft68. The fenestration 82 is aligned with the struts 84 and 86 of thedistal internal self expanding zig zag stent 78 so that the sides of thefenestration 90 can be stitched by stitching 92 to the struts 84 and 86along at least part of their length.

Radiopaque or MRI opaque markers 94 are provided each side of thefenestration another marker 96 is provided at the base of thefenestration to enable visualisation of the fenestration to an accurateposition with respect to a branch vessel such as a coeliac artery.

Once again, it will be noted that when the stent graft 68 is compressedfor deployment within a delivery device the fenestration 82 will closeup but upon release the fenestration will open to provide access to thebranch artery.

FIG. 13A shows an alternative arrangement of a scalloped fenestration.In this embodiment the struts 93 and 95 of a zig-zag stent 97 are bentso that a more U-shaped fenestration 98 can be formed in the stent graft99.

FIG. 14 shows an alternative embodiment of a stent graft with ascalloped fenestration and FIG. 15 shows a detailed internal view of thescalloped fenestration of FIG. 14.

In FIG. 14 the stent graft 100 comprises a tubular wall body of graftmaterial 102 with a lumen therethrough. The distal end 104 of the stentgraft has distally extending exposed stent 106 and within the tubularwall body 102 there are proximal and distal internal stents 108 and 110respectively and at least one external stent 80 intermediate theproximal distal ends. A fenestration is provided at the distal end 104of the stent graft 100. Stent 107, shown here as an internal stent,comprises a plurality of struts. As shown, struts 117 and 118 compriseadjacent struts, and struts 115 and 116 comprise adjacent struts. Inthis embodiment the fenestration 114 is in the form of a scallopedfenestration extending from the distal end 104 of the stent graft 100toward the proximal end 102 of the stent graft. The scallopedfenestration 114 has three sides 119, 121, and 131. Sides 119 and 121,as shown in FIGS. 12, 13, 13A, 14, 15 are substantially longitudinal,whereas side 131 is a substantially lateral side. As shown in FIGS. 14and 15, the scalloped fenestration 114 is aligned with spaced apartstruts 116 and 118 of the distal internal self expanding zig zag stent110 so that the sides 119, 121, and 131 of the fenestration 114 can bestitched by stitching 120 to the struts 116 and 118 along at least partof their length. As shown in FIGS. 12, 13, 13A, 14 and 15, the stitchingmay be on some of the sides, all of the sides, or a portion of one ormore of the sides. As shown in FIG. 14, zig-zag portion 122 of thedistal internal self expanding zig zag stent 110 extends uncoveredthrough the fenestration and suture 124 joins a bend of the distallyextending exposed stent 106 to a bend of the distal internal selfexpanding zig zag stent 110. As FIGS. 14 and 15 show, the length of thelateral side 131 is greater than the minimum distance between any twoadjacent struts, for example lateral side 131 has a length that islonger than the minimum distance between adjacent struts 115 and 116.This feature is also shown in FIGS. 12 and 13. As FIGS. 14 and 15 alsoshow, the length of the lateral side 131 also may be greater than themaximum distance between adjacent struts.

The enlarged fenestration of this embodiment is illustrated as a doublewidth as it takes in regions between two pairs of struts of the stentbut may also be provided as a triple width. The enlarged fenestrationenables a stent graft to be placed where there are several branchvessels in close proximity to each other which should not be occluded.

The scalloped fenestration shown in FIGS. 12 to 15 have been illustratedas being on the distal end of a stent graft but they may also beprovided on the proximal end of a stent graft with or without theuncovered self expanding stent.

The use of a resilient reinforcement around the periphery of thefenestration provides a much more dimensionally stable aperture for thedeployment of a leg or side arm extension. Particularly if using aballoon expandable stent as a leg or side arm extension is used theforce of the balloon expansion will not tend to tear the graft materialwhich may occur if no reinforcement was provided. The resiliency allowsthe fenestration to close off during contraction for deployment but toopen up to a desired size and shape upon release in situ.

Throughout this specification various indications have been given as tothe scope of this invention but the invention is not limited to any oneof these but may reside in two or more of these combined together. Theexamples are given for illustration only and not for limitation.

Throughout this specification and the claims that follow unless thecontext requires otherwise, the words ‘comprise’ and ‘include’ andvariations such as ‘comprising’ and ‘including’ will be understood toimply the inclusion of a stated integer or group of integers but not theexclusion of any other integer or group of integers.

What is claimed is:
 1. A stent graft comprising a tubular body definedby a tubular wall and comprising a first end and a second end, thetubular wall being formed from a biocompatible graft material and havingan internal lumen and an internal wall, terminal self expanding stentportion disposed within the tubular lumen at the first end and abuttingat least a portion of the internal wall, the internal terminal selfexpanding stent portion comprising struts and bends between the struts,only a single U shaped scalloped fenestration which is open at one sidein the tubular wall provided at the first end of the tubular wall, thesingle scalloped fenestration including a periphery, the peripheryextending between a pair of struts, the pair of struts at leastpartially defining the single U shaped scallop fenestration in thebiocompatible graft material between the pair of struts, thebiocompatible graft material being stitched to the pair of struts atleast partially around the periphery of the single U shaped scallopedfenestration, whereby during deployment the bent struts of the internalterminal zig zag self expanding stent assist with opening up of thesingle U shaped scalloped fenestration into the U shape.
 2. A stentgraft as in claim 1 further including at least a second fenestration inthe tubular wall intermediate the first end and the second end of thetubular body, the second fenestration including a second periphery andreinforcement around the second periphery, whereby the ring providesdimensional stability to the second fenestration to assist with sealingfor deployment of a side arm extension therein.
 3. A stent graft as inclaim 2 wherein the reinforcement comprises a ring comprises at leasttwo turns of the resilient wire.
 4. A stent graft as in claim 3 whereinterminal ends of the resilient wire of the ring are provided with aloop, whereby the wire does not present a pointed end of wire whichcould damage a vessel.
 5. The stent graph of claim 1 further comprisinga second stent proximally adjacent the internal terminal stent andextending from the first end.
 6. The stent graft of claim 1 wherein thestent has a distance between the pair of struts, as measured from onesubstantially longitudinal strut to the other substantially longitudinalstrut, defining the single U shaped scalloped fenestration, and thedistance between the pair of struts defining the single U shapedscalloped fenestration is greater than a distance between another pairof adjacent struts.
 7. A stent graft comprising a tubular body ofbiocompatible graft material having: a proximal end, proximal endopening, and a proximal end opening edge, a distal end, a distal endopening, and a distal end opening edge, a lumen between the proximal endopening and distal end opening, an internal terminal stent disposedwithin the lumen of the stent graft distal of the proximal end openingsuch that the graft material at least partially encloses the stentwithin the lumen, and only a single scallop in the graft material at theproximal end of the graft material extending distally from the proximalend opening edge and having a periphery, wherein the internal stentcomprises at least two struts that extends along, defines, and supportsat least a portion of the periphery of the single scallop, wherein theinternal stent comprises a self-expanding stent having apices andstruts, wherein the single scallop is disposed between a pair of apices,wherein the distance between the pair of apices, as measured from apexto apex, is greater than a minimum distance between any other pair ofapices that are adjacent to each other.
 8. The stent graft of claim 7further comprising at least one fenestration in the graft material. 9.The stent graft of claim 7 where the portion of the internal stentextending along and supporting the periphery of the single scallop isstitched to the periphery.
 10. A stent graft comprising: a tubular bodyof biocompatible graft material, a first end and a first end opening, asecond end and a second end opening, a lumen between the first andsecond ends, an internal terminal stent disposed within the lumen of atleast one of the ends of the stent graft and at least partially coveredby the graft material, only a single scallop in the graft material atone of the ends of the stent graft, the single scallop having aperiphery, a first frame supporting at least a portion of the peripheryof the single scallop, at least two fenestrations having a perimeter,separate from the single scallop, formed in the graft material, and eachfenestration having a frame separate from the stent supporting at leasta portion of the perimeter of each fenestration.
 11. The stent graft ofclaim 10 wherein a portion of the internal terminal stent comprises theframe of the single scallop.